WO2008063032A1

WO2008063032A1 - End point detecting apparatus and method of bobbin printing bar code and winding division thread

Info

Publication number: WO2008063032A1
Application number: PCT/KR2007/005962
Authority: WO
Inventors: Hoon-Sik Cho
Original assignee: Hoon-Sik Cho
Priority date: 2006-11-23
Filing date: 2007-11-23
Publication date: 2008-05-29

Abstract

An apparatus for detecting the tail end of bobbin thread wound in separate regions around a barcode-printed bobbin is provided. Bars of a barcode are printed separately in multiple sections on the outer surface of the bobbin, and store respective position information of the multiple sections. The thread is wound to predetermined lengths respectively in separate regions around the bobbin, divided into the sections according to the printed bars, while covering the barcode. A detector includes an LED and a light receiving sensor provided in a side opening of a bobbin case. The LED emits light to the printed barcode when the thread is exhausted and the light receiving sensor detects returning light. A controller includes a decoder, setting unit, and processor. The decoder converts a barcode value read by the detector into digital. The setting unit receives a preset value corresponding to a position of one of sequential remaining amounts of thread represented by the barcode. The processor determines whether the digital value is identical to the preset value. A notification unit includes a speaker and lamp for notifying, when the wound thread is exhausted, the worker of the exhaustion according to the digital value.

Description

END POINT DETECTING APPARATUS AND METHOD OF BOBBIN PRINTING BAR CODE AND WINDING DIVISION

THREAD

Technical Field

[1] The present invention relates to an apparatus and method for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin, and more particularly to a method and apparatus for detecting the tail end of a bobbin thread wound in separate regions around a bobbin printed with a barcode to inform the worker, who is doing a sewing work, of the remainder of the bobbin thread, i.e., of whether or not the remaining amount of the bobbin thread is enough to complete the current work. Background Art

[2] Generally, termination of needle thread (or upper thread) during a sewing work rarely causes problems since the needle thread is very long (3000-400Om) and the worker can also view the needle thread. However, in the case of relatively thick 280D/3 bobbin thread (or lower thread), there are various problems relating to determining the time to replace the bobbin thread since the thick bobbin thread must be short (about 20m) and thus must often be replaced.

[3] FIGS. 1 and 2 illustrate a related art apparatus for supplying a bobbin thread in a sewing machine which can detect the remainder of the bobbin thread, which is described in Korean Registered Patent Publication No. 10-0471639. As shown, a rotary hook 100, which is rotatably coupled to the sewing machine, includes an electrode plate 180 coupled to a rotating shaft 170 and a light receiving sensor 110 which is connected at one end to the electrode plate 180 and is connected at the other end to a body 150. The light receiving sensor 110 is inserted into an internal housing by passing through a central portion of the rotating shaft 170 and the body 150. A light source 500, which emits light to a rear-side through portion 160 of the rotary hook 100, is coupled to the sewing machine at a position adjacent to the rotary hook 100. A bobbin shaft 250 of the bobbin case has a through hole 260 through which light passes to enter a cavity 220 of the bobbin case via the rear-side through portion 160 of the rotary hook 100. A reflecting plate 265 is coupled at a specific angle to an inner portion of the shaft in order to transfer light, which has passed through the through hole 260 of the shaft, to the light receiving sensor 110 of the rotary hook 100. A coupling pipe 450 of the shuttle 400 has a through hole 460 corresponding to the through hole 260 formed in the shaft 250 of the bobbin case. The bobbin 300 is constructed to allow light, which has sequentially passed through the rear-side through portion 160 of the rotary hook 100 and the cavity 200 of the bobbin case, to be transferred to the through hole 460 formed in the coupling pipe 450 of the shuttle and the through hole 260 formed in the shaft 250 of the bobbin case. A detection circuit 600 is also provided to generate a signal to notify the worker of absence of the bobbin thread when the bobbin thread wound around the bobbin 300 is completely exhausted. The detection circuit 600 includes a power supply 610 with two polarities, which are connected respectively to the electrode plate 180 and the rotary hook body 150, and a signal generator 620 that generates a signal according to light detected by the light receiving sensor 110.

[4] However, the related art has the following problems. The apparatus does not achieve highly accurate detection and also requires high processing costs since the apparatus uses a general optical sensor to detect the remainder of the bobbin thread and it is also necessary to accurately process the inner portion of the shaft of the bobbin case, the bobbin, etc.

[5] The detection apparatus using the optical sensor also has a problem in that, even when the bobbin thread is not completely unwound, light begins to pass through or be reflected from the bobbin since the thickness of the bobbin thread is small to cause the apparatus to determine that the bobbin thread has been completely exhausted, thereby failing to accurately detect the remainder of the bobbin thread. Disclosure of Invention

Technical Problem

[6] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an apparatus and method for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin, wherein bars of a barcode are printed on divided sections of the bobbin so that the bars can be read by a detector including an LED and a light receiving sensor to detect the bobbin thread that are unwound as a work proceeds, and wherein the bobbin thread is wound stepwise to predetermined lengths respectively in separate regions around the bobbin such that, as a work proceeds, the bobbin thread wound in the separate regions is sequentially exhausted to expose the barcode, thereby providing a function to inform the worker of the remainder of the bobbin thread or to deactivate the sewing machine when the remainder of the bobbin thread becomes the same as that preset by the worker. Technical Solution

[7] In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of an apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin, wherein a fixed shaft protruding from an inner surface of a bobbin case is inserted into the bobbin wound with the bobbin thread that passes over and under a needle thread to sew clothes in a sewing machine, the apparatus comprising a barcode having bars printed separately in multiple sections on an outer surface of the bobbin, the bars storing respective position information of the multiple sections; a bobbin thread wound to predetermined lengths respectively in separate regions around the bobbin, which is divided into the multiple sections according to the printed bars, while covering the barcode; a detector including an LED and a light receiving sensor provided in a side opening of a bobbin case, wherein the LED emits light to the barcode printed on the outer surface of the bobbin when the bobbin thread is exhausted and the light receiving sensor detects returning light; a controller including a decoder, a setting unit, and a processor, the decoder converting a value of the barcode read by the detector into a digital value, the setting unit receiving a preset value corresponding to a position of one of sequential remaining amounts of thread represented by the barcode, the processor determining whether the digital value is identical to or different from the preset value; and a notification unit including a speaker and a lamp for notifying, when the bobbin thread wound in the separate regions around the bobbin is exhausted, a worker of the exhaustion of the bobbin thread according to the digital value output by the decoder.

[8] A space around the outer surface of the bobbin is divided into a first region, a second region, a third region, and a fourth region with predetermined sizes and the bobbin thread is first wound to a predetermined length in the first region and is then consecutively wound to predetermined lengths respectively in the second region, the third region, and the fourth region and is then sequentially wound in a fifth region that covers an entire top of the first to fourth regions.

[9] A through hole having a specific size allowing the bobbin to be exposed is formed through an outer surface of the bobbin case and the detector is provided to read the barcode through the through hole.

[10] The present invention also provides a method for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin during a sewing work, the method comprising the steps of SlO) reading a value of a barcode on an outer surface of a bobbin when the barcode is exposed as a bobbin thread is unwound; S20) converting the value of the barcode into a digital value; S30) comparing the digital value with a previously input reference value corresponding to a predetermined position on the outer surface of the bobbin; S40) presenting that the digital value is identical to the reference value; S50) obtaining a thread cutting signal of the bobbin thread through a thread cutting detector and determining the time to alarm; and S60) deactivating a sewing machine according to the thread cutting signal or indicating, through a speaker or a lamp, that the bobbin thread has been cut.

Advantageous Effects

[11] As described above, in the apparatus and method for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to the present invention, the bobbin thread is wound in separate regions on the bars of the barcode printed in multiple sections on the outer surface of the bobbin. Accordingly, the detector detects the bars of the barcode that are exposed as the bobbin thread wound in the separate regions is exhausted and informs the worker of the detection, thereby preventing, and alarming the worker of, failures caused by threadless sewing and the need to cut and connect the current bobbin thread to another bobbin thread. This prevents broken stitches and an increase in the cost due to reworks, thereby improving the productivity.

[12] In addition, the bobbin thread can be wound to various lengths required by the worker respectively in separate regions around the bobbin. Using the barcode, which is exposed as the bobbin thread wound in each separate region is exhausted, the remainder of the bobbin thread can be recognized and predicted, thereby increasing the efficiency of the sewing work. Brief Description of the Drawings

[13] FIG. 1 is a cross-sectional view of a related art apparatus for supplying a bobbin thread in a sewing machine which detects the remainder of the bobbin thread;

[14] FIG. 2 illustrates the configuration of the related art apparatus for supplying a bobbin thread in a sewing machine;

[15] FIG. 3 is a perspective view of an apparatus for detecting the tail end of a bobbin th read wound in separate regions around a barcode-printed bobbin according to the invention;

[16] FIG. 4 is an exploded perspective view of the apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to the invention;

[17] FIG. 5 is a cross-sectional view of the barcode-printed bobbin in the apparatus for detecting the tail end of the bobbin thread wound in separate regions around the barcode-printed bobbin according to the invention;

[18] FIG. 6 is a cross-sectional view of an apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to another embodiment of the invention;

[19] FIG. 7 is a cross-sectional view of a bobbin thread of the apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to the invention; [20] FIG. 8 is a flow chart of a bobbin thread detection method of the apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode- printed bobbin according to the invention; and

[21] FIG. 10 illustrates usage of the apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to the invention.

[22] <Reference Numerals of Main Parts of the Drawings>

[23] 10: bobbin case 11: opening

[24] 12: fixed shaft 13: outer surface

[25] 14: through hole 20: bobbin

[26] 21: outer surface 30: barcode

[27] 40: bobbin thread 41 : first region

[28] 42: second region 43: third region

[29] 44: fourth region 45: fifth region

[30] 50: detector 51: LED

[31] 52: light receiving sensor 60: controller

[32] 61: decoder 62: setting unit

[33] 63: processor 70: notification unit

[34] 71: speaker 72: lamp

Mode for the Invention

[35] Operations and features of the preferred embodiments of an apparatus and method for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to the present invention will now be described in detail with reference to the accompanying drawings.

[36] FIG. 3 is a perspective view of an apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to the invention, FIG. 4 is an exploded perspective view of the apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to the invention, FIG. 5 is a cross-sectional view of the barcode-printed bobbin in the apparatus for detecting the tail end of the bobbin thread wound in separate regions around the barcode-printed bobbin according to the invention, FIG. 6 is a cross-sectional view of an apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to another embodiment of the invention, FIG. 7 is a cross-sectional view of a bobbin thread of the apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to the invention, FIG. 8 is a flow chart of a bobbin thread detection method of the apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to the invention, and FIG. 10 illustrates usage of the apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to the invention.

[37] The apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to the invention includes a bobbin case 10 and a bobbin 20. As with a general sewing machine (not shown), the bobbin case 10, which is provided inside a hook (not shown), is closed at one side and has an opening 11 at the opposite side and the bobbin 20 with an outer surface 21, around which a bobbin thread 40 is wound, is coupled to a fixed shaft 12 protruding from an inner surface of the bobbin case 10 such that the fixed shaft 12 is inserted in the bobbin 20.

[38] Particularly, a barcode 30 with bars, in which respective position information of multiple sections of the outer surface 21 of the bobbin 20 is stored, is printed on the outer surface 21 of the bobbin 20 such that the outer surface 21 of the bobbin 20 is divided into the multiple sections according to the printed bars. The apparatus further includes a bobbin thread 40, a detector 50, a controller 60, and a notification unit 70. The bobbin thread 40 is wound in separate regions around the bobbin 20 above the barcode 30. The detector 50 includes an LED 51 which emits light to the barcode 30 when the bobbin thread 40 on the barcode 30 is exhausted and a light receiving sensor 52 which detects returning light. The controller 60 analyzes and compares a barcode value read by the detector 50 with a preset value. The notification unit 70 includes a speaker 71 and a lamp 72 to notify the worker when the bobbin thread 40 is exhausted.

[39] The bobbin 20 may have an H-shaped structure or a straight tubular structure to wind the bobbin thread 40 around the bobbin 20. When the bobbin 20 is H-shaped, partition walls may be formed on the bobbin 20 to divide the regions around the bobbin 20. When the bobbin 20 is straight-tubular, small-height partition walls may be formed on the bobbin 20.

[40] As shown in FIGS. 3 and 4, the bars of the barcode 30 are printed or marked at predetermined intervals on one or both sides of the outer surface 21 of the bobbin 20. When part of the bobbin thread 40 wound around the bobbin 20 is unwound to expose some bar of the barcode 30, the detector 50 detects the exposed bar, thereby determining where the bobbin thread 40 is located on the outer surface 21 of the bobbin 20 according to the barcode 30.

[41] The barcode 30 may be a barcode indicating multiple steps rather than a general barcode having a code indicating the start and end. The barcode 30 may be printed with various forms such as wide and narrow bars or patterns arranged at small and large intervals. [42] In one embodiment of the barcode 30, bars of the barcode 30 are printed on a plurality of regions into which the outer surface 21 of the bobbin 20 is divided, so that each bar of the barcode 30 is exposed as a portion of the bobbin thread 40 wound on a corresponding one of the divided regions is exhausted. The present invention aims to detect the exposed bar, thereby detecting the exhaustion of the bobbin thread 40. The barcode 30 may be a one-dimensional barcode including lines or a two-dimensional barcode including areas.

[43] In another embodiment, the barcode 30 may be a UV barcode with a general format including wide and narrow bars arranged at small and large intervals that are printed using ink including a UV dye which is fluorescent dye. In this embodiment, a conventional UV LED and a conventional light receiving sensor which can detect wavelengths of the UV dye are used as the LED 51 and the light receiving sensor 52.

[44] In another embodiment, the barcode 30 may be a color barcode having color bars with various colors and widths. In this embodiment, a conventional color sensor or CMOS sensor can also be used. Various embodiments of the barcode 30, other than those described above, can be provided to achieve the object of the present invention.

[45] The bobbin thread 40 is wound around the bobbin 20 which is divided into multiple sections according to the barcode 30. As shown in FIG. 7, the bobbin thread 40 is wound around the bobbin 20 sequentially in separate regions, a first region 41, a second region 42, a third region 43, and a fourth region 44, in which the bars of the barcode 30 have been printed on the outer surface 21 of the bobbin 20, and the remainder of the bobbin thread 40 is then wound in a fifth region 45 which covers the entire top of the first to fourth regions 41 to 44, without being in contact with the outer surface 21.

[46] The bobbin thread 40 is wound around the bobbin 20 in separate regions through a multi-sectional winder (not shown). A multi- sectional winder controller (not shown) sets a desired length of the bobbin thread 40 to be wound around the bobbin 20. When the set length of the bobbin thread 40 is wound around the bobbin 20 as the bobbin thread 40 passes through a length measurement device (not shown), another desired length of the bobbin thread 40 is continuously wound in the next region around the bobbin 20 using a lever (not shown) that moves the bobbin thread 40 horizontally.

[47] In an embodiment, the multi- sectional winder (not shown) winds the bobbin thread

40 in the separate regions around the bobbin 20 such that a length of 50cm of the bobbin thread 40 is wound in the first region 41, a length of 20cm is wound in the second region 42, a length of 20cm is wound in the third region 43, a length of 20cm is wound in the fourth region 44, and a length of 1800cm is wound in the fifth region 45.

[48] For example, a labeling (attachment sewing) work requiring a thread of 50cm is performed using the bobbin 20 that is wound with the bobbin thread 40 as described above, 1st to 29th labeling works are completed using the bobbin thread 40 wound in the second to fifth regions 42 to 45 and the bobbin thread 40 wound in the second region 42 is exhausted during a 60th labeling work. The detector 50 detects the barcode 30 exposed as the bobbin thread 40 wound in the second region 42 is exhausted and then activates the lamp 72 or the speaker 71 to generate light or sound. Upon recognizing the light or sound, the worker terminates the 30th labeling work and replaces the bobbin 20 wound with the bobbin thread 40 with a new one and then performs a 31st labeling work. If the worker has not replaced the bobbin 20 after terminating the 30th labeling work, the bobbin thread 40 will be exhausted during the 31st labeling work, causing threadless sewing failures.

[49] As described above, the worker can wind the bobbin thread 40 around the outer surface 21 of the bobbin 20 by combining various methods, taking into consideration the remainder of the bobbin thread 40 and the amount of work to be done.

[50] Meanwhile, in order to detect the barcode 30 and notify the worker of the detection, the detector 50 includes the LED 51 and the light receiving sensor 52 to read the barcode 30 printed on the outer surface 21 of the bobbin 20. The controller 60 includes a decoder 61 that converts a read value of the barcode into a digital value. The controller 60 also includes a processor 63 that compares the converted digital value with a reference value preset at a setting unit 62 and drives the speaker 71 or the lamp 72 according to the comparison. The notification unit 70 includes the speaker 71 or the lamp 72 that is driven according to the processing result of the processor 63.

[51] Here, the reference value corresponds to a specific position on the outer surface 21 of the bobbin 20. The reference value may be preset in the setting unit 62 to inform, when the bobbin thread 40 is unwound so that a desired amount of the bobbin thread 40 remains, the worker that the desired amount of the bobbin thread 40 remains. Without being preset, the reference value may be included in the detector 50 as part of the function of the detector 50 such that it is implemented as a value alarming the worker of complete exhaustion of the bobbin thread 40 when the detector 50 detects a specific value of the barcode 30.

[52] As shown in FIG. 8, a method for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin according to the invention includes the steps of SlO) reading a value of a barcode 30 on an outer surface 21 of a bobbin 20 when the barcode 30 is exposed as a bobbin thread 40 is unwound; S20) converting the value of the barcode 30 into a digital value; S30) comparing the digital value with a previously input reference value corresponding to a predetermined position on the outer surface 21 of the bobbin 20; S40) indicating that the digital value is identical to the reference value; S50) obtaining a thread cutting signal of the bobbin thread 40 through a thread cutting detector (not shown) and determining the time to alarm; and S60) deactivating a sewing machine according to the thread cutting signal or indicating, through a speaker 71 or a lamp 72, that the bobbin thread 40 has been cut.

[53] The following is a more detailed description of the method.

[54] The LED 51 emits light to the bobbin 20 that is exposed as the bobbin thread 40 is unwound and the light receiving sensor 52 receives the light reflected from the outer surface 21 of the bobbin 20 to read a value of the barcode 30 on the outer surface 21 at the barcode read step SlO. The read analog value of the barcode 30 is amplified through an amplifier (not shown).

[55] At the conversion step S20, the decoder 61 converts the amplified analog value of the barcode 30 into a digital value, which is then displayed as an accurate number to inform the worker of presence or absence of the bobbin thread 40 at a corresponding position on the outer surface 21 of the bobbin 20.

[56] Specifically, the digital value produced by the conversion of the read value of the barcode 30 through the decoder 61 is transferred to the processor 63. At the com parison step S30, the processor 63 then compares the digital value with a reference value preset through the setting unit 62 and determines whether or not the digital value is identical to the reference value. If it is determined that the digital value is identical to the reference value, the processor 63 outputs the determination to the notification unit 70 (S40).

[57] When the detector 50 detects the tail end of the bobbin thread 40, the processor 63 stores the detection information. When the work is ended, the controller 60 transfers an end signal to the sewing machine and obtains a thread cutting signal from a thread cutter (not shown) which cuts the bobbin thread 40 and determines the time to alarm (S50). The controller 60 then performs a display step S60 at which it activates the speaker 71 or the lamp 72 which is the notification unit 70 according to the thread cutting signal from the thread cutter. The notification unit 70 is not limited to the speaker 71 or the lamp 72 and its various embodiments such as an LCD or LED display may be provided.

[58] As shown in FIG. 9, the alarm is activated after the current work in this manner to notify the worker that the sewing machine has been stopped and that the bobbin thread 40 should be replaced if the remainder of the bobbin thread 40 can complete only the current work, i.e., if the remainder of the bobbin thread 40 is not enough to perform the next work. This eliminates the need for the worker to care about the remainder of the bobbin thread 40 during the work, thereby removing the worker's anxiousness, and also prevents threadless sewing that would otherwise occur when the bobbin thread 40 is exhausted.

[59] Meanwhile, the worker can preset the time to alarm the worker of the tail end of the bobbin thread 40 through the setting unit 62. Specifically, through the setting unit 62, the worker can set a desired remainder of the thread to alarm, control the alarm volume, the alarm type (speaker or lamp), and the time to alarm.

[60] Here, the time to alarm can be divided into the time during work and the time after work. In the case where the alarm is activated during work, the alarm is to notify the worker of the remainder of the bobbin thread 40 during a sewing work. In this case, the time to alarm during work is set through the setting unit 62. Then, at the set time to alarm, a digital value produced by conversion of a read value of the barcode 30 of the outer surface 21 of the bobbin 20 is compared with a preset value to notify the worker of a preset remainder of the bobbin thread 40.

[61] On the other hand, the bars of the barcode 30 are printed at predetermined positions on one or both sides of the outer surface 21 of the bobbin 20, where each printed bar has a value representing a corresponding position. During a sewing work, the bobbin thread 40 wound around the bobbin 20 is unwound and used in the order from that wound in the fifth region 45 to that of the first region 41. When the barcode 30 is exposed as the bobbin thread 40 is unwound, the notification unit 70 notifies the worker of the exposure of the barcode 30.

[62] In an example, position values are defined in three steps on the outer surface 21 of the bobbin 20 to alarm the worker of the tail end of the bobbin thread 40 of the outer surface 21 of the bobbin 20. In this example, the values of the barcode 30 printed on the outer surface 21 of the bobbin 20 may be represented by 0, 1, and 2, which indicate the respective positions on the outer surface 21 of the bobbin 20 that are sequentially exposed as the bobbin thread 40 wound around the bobbin 20 is unwound from the outer side to the inner side of the outer surface 21 of the bobbin 20.

[63] Specifically, when a bar of "0" is exposed as the bobbin thread 40 wound on an outer side of the bobbin 20 is unwound, the detector 50 reads and converts the exposed bar value into a binary value of "00" as a digital value. The controller 60 compares the converted digital value with a preset value and activates the notification unit 70 if the digital value is identical to the preset value. In the same manner, the position "1" on the outer surface 21 of the bobbin 20 is converted into a binary value "01" to be used as described above and the position "2" on the outer surface 21 of the bobbin 20 is converted into a binary value "10".

[64] Here, the binary values "00", "01", and "10" indicate patterns of the bars of the barcode 30, which may be identical or different. Each of the patterns is a specific arrangement of one or more bars with large and small thicknesses. Combinations of wide and narrow bars can provide various patterns.

[65] Although three detection positions are defined on the outer surface 21 of the bobbin

20 in order to detect the tail end of the bobbin thread 40 in this example, any other multiple detection positions may be defined such that the tail end of the bobbin thread 40 is detected in multiple steps. The values of the barcode 30 may be defined as specific values rather than sequential values as described above.

[66] FIG. 6 illustrates an apparatus for detecting the tail end of a bobbin thread wound in separate regions on a barcode-printed bobbin according to another embodiment of the invention. In this embodiment, the apparatus includes a detector 50 located at a different position from that of the detector 50 of FIG. 5. A through hole 14 having a size allowing insertion of the detector 50 is formed through the outer surface 13 of a bobbin case 10 and the detector 50 is fixed in the through hole 14 to read a barcode 30 on the outer surface 21.

[67] As is apparent from the above description, the present invention has the following advantages. First, the bobbin thread is wound in separate regions on the bars of the barcode printed in multiple sections on the outer surface of the bobbin. Accordingly, the detector sequentially detects the bars of the barcode that are exposed as the bobbin thread wound in the separate regions is exhausted and informs the worker of the detection, thereby preventing, and alarming the worker of, failures caused by threadless sewing and the need to cut and connect the current bobbin thread to another bobbin thread. This prevents broken stitches and an increase in the cost due to reworks, thereby improving the productivity.

[68] In addition, the bobbin thread can be previously wound to various lengths, such as

50cm, 70cm, 100cm, and 150cm, desired by the worker respectively in separate regions around the bobbin. Using the barcode, which is exposed as the bobbin thread wound in each separate region is exhausted, the remainder of the bobbin thread can be recognized and predicted, thereby increasing the efficiency of the sewing work.

[69] Further, by providing a work place with the bobbin around which the bobbin thread is wound to various lengths respectively in separate regions, it is possible to eliminate the inconvenience of the sewing worker having to manually wind the bobbin thread in the work place, thereby further improving the productivity.

[70] The present invention is not limited to the specific preferred embodiments described above. Anyone having ordinary skill in the art will be able to implement various modifications without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Such modifications should be construed as being included in the scope of the invention described in the claims.

Claims

[1] An apparatus for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin, wherein a fixed shaft protruding from an inner surface of a bobbin case is inserted into the bobbin wound with the bobbin thread that passes over and under a needle thread to sew clothes in a sewing machine, the apparatus comprising: a barcode 30 with bars printed separately in multiple sections on an outer surface 21 of the bobbin 20, the bars storing respective position information of the multiple sections; a bobbin thread 40 wound to predetermined lengths respectively in separate regions around the bobbin 20, which is divided into the multiple sections according to the printed bars, while covering the barcode 30; a detector 50 including an LED 51 and a light receiving sensor 52 provided in a side opening 11 of a bobbin case 10, wherein the LED 51 emits light to the barcode 30 printed on the outer surface 21 of the bobbin 20 when the bobbin thread 40 is exhausted and the light receiving sensor 52 detects returning light; a controller 60 including a decoder 61, a setting unit 62, and a processor 63, the decoder 61 converting a value of the barcode 30 read by the detector 50 into a digital value, the setting unit 62 receiving a preset value corresponding to a position of one of sequential remaining amounts of thread represented by the barcode 30, the processor 63 determining whether the digital value is identical to or different from the preset value; and a notification unit 70 including a speaker 71 and a lamp 72 for notifying, when the bobbin thread 40 wound in the separate regions around the bobbin 20 is exhausted, a worker of the exhaustion of the bobbin thread 40 according to the digital value output by the decoder 61.

[2] The apparatus according to claim 1, wherein a space around the outer surface 21 of the bobbin 20 is divided into a first region 41, a second region 42, a third region 43, and a fourth region 44 with predetermined sizes and the bobbin thread 40 is first wound to a predetermined length in the first region 41 and is then consecutively wound to predetermined lengths respectively in the second region 42, the third region 43, and the fourth region 44 and is then sequentially wound in a fifth region 45 that covers an entire top of the first to fourth regions 41 to 44.

[3] The apparatus according to claim 1, wherein a through hole 14 having a specific size allowing the bobbin 20 to be exposed is formed through an outer surface 13 of the bobbin case 10 and the detector 50 is provided to read the barcode 30 through the through hole 14. [4] A method for detecting the tail end of a bobbin thread wound in separate regions around a barcode-printed bobbin during a sewing work, the method comprising the steps of:

SlO) reading a value of a barcode 30 on an outer surface 21 of a bobbin 20 when the barcode 30 is exposed as a bobbin thread 40 is unwound; S20) converting the value of the barcode 30 into a digital value; S30) comparing the digital value with a previously input reference value corresponding to a predetermined position on the outer surface 21 of the bobbin 20; S40) indicating that the digital value is identical to the reference value; S50) obtaining a thread cutting signal of the bobbin thread 40 through a thread cutting detector and determining the time to alarm; and S60) deactivating a sewing machine according to the thread cutting signal or indicating, through a speaker 71 or a lamp 72, that the bobbin thread 40 has been cut.